Curtius28 schreef:
I'm not trying to hack into somebody else's router. it's my router, and I pay a valid subscription. I don't get why I shouldn't simply know the password and make the best use of it.
You pay for a service which includes a modem/router which is owned by T-Mobile, the modem/router (Zyxel) is thus not owned by you.
To avoid customers causing issues that (in the end) might result into connection, performance or any other kind of issues, T-Mobile has disabled services that are not important for the “average” customer.
Non-average customers thus, those who do require additional services can buy their own modem/router and connect their own device.
Curtius28 schreef:
If T-mobile would not be able to support me with the “advanced” features of the router, I can sign a form to give up on technical support.
No there is no such form. Theere is no minimum requirement of functionality offered by the modem.